Lunyu III. 15. (55)

Confucius in the grand temple.
The Master, when he entered the grand temple, asked about everything. Some one said, "Who say that the son of the man of Tsâu knows the rules of propriety! He has entered the grand temple and asks about everything." The Master heard the remark, and said, "This is a rule of propriety."

Legge III.15.

When the Master went inside the Grand Temple, he asked questions about everything. Someone remarked, 'Who said that the son of the man from Tsou understood the rites? When he went inside the Grand Temple, he asked questions about everything.'
The Master, on hearing of this, said, 'The asking of questions is in itself the correct rite.'